---
title: "CVE-2026-94447: Checksum database bypass for golang.org/toolchain in cmd/go"
url: https://erroneo.us/security/cve/CVE-2026-94447/
description: "CVE-2026-94447 (Go toolchain cmd/go): Previously, a user operating inside of a malicious Go project that defines a bogus golang.org/toolchain go.sum entry…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-10-08
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-94447"
kev: false
cvss: 7.8
epss: 0.00103
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-94447: Checksum database bypass for golang.org/toolchain in cmd/go

**Signal:** Normal patch cycle. No exploitation signal; fix it in your next routine update if you are affected. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.1% , percentile 1: FIRST’s model estimates a 0.1% chance of exploitation activity in the next 30 days, higher than 1% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
- Editorial verdict: Patch this week. Go October 2026 Security Releases: 16 Stdlib Fixes — Rebuild and redeploy Go services with Go 1.27.3 or 1.26.10 this week, starting with internet-facing HTTP/2 servers and reverse proxies; none of these bugs is known to be exploited.

## What it is

Previously, a user operating inside of a malicious Go project that defines a bogus golang.org/toolchain go.sum entry and operates a malicious GOMODPROXY the user chooses to use can bypass the intended checksum. We now ensure that golang.org/toolchain always goes to the network for the canonical checksum.

## Affected products (CVE record)

- Go toolchain cmd/go: < 1.26.9, 1.27.0-0 < 1.27.2

## Severity

- CISA-ADP CVSS 3.1: 7.8 `CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.10% probability of exploitation activity in the next 30 days; percentile 1.

## Sources

- [CVE.org record CVE-2026-94447](https://www.cve.org/CVERecord?id=CVE-2026-94447)
- [NVD entry CVE-2026-94447](https://nvd.nist.gov/vuln/detail/CVE-2026-94447)
- [go.dev](https://go.dev/cl/840785)
- [go.dev](https://go.dev/issue/81834)
- [groups.google.com](https://groups.google.com/g/golang-announce/c/U2fTuyDJznI)
- [pkg.go.dev](https://pkg.go.dev/vuln/GO-2026-6602)

---
Source page: https://erroneo.us/security/cve/CVE-2026-94447/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt